Thermic siphon



June 8, 1943- G. J. cHRlsTENsoN THERMIC SYPHON Filed May 20, 1940 2Sheets-Sheet 1 f Illllnlllllll Y .f l

Mwfw/ ewa@ THERMIC SYPHON Filed May 20, 1940 2 Sheets-Sheet 2 ms; /C-Cqm Patented June 8, 1943 THERMIC SEPI-ION Gust J. Christensen,Chicago, Ill., assigner to Locomotive Firebox Company, Chicago, Ill., a

corporation of Delaware Application May 20, 1940, Serial No. 336,162

2 Claims.

This invention relates to -improvements in thermic siphons and itconsists of the matters hereinafter described and more particularlypointed out in the appended claims. The present invention is moreespecially concerned with siphons of the so-called duplex type, whereinthe body thereof has more than one water inlet, as distinguished fromsiphons of the so-called Nicholson type, wherein the body has only onewater inlet.

- A siphon of either type may well be used in a locomotive boileriirebox requiring only one siphon. However, thermic siphons arefrequently used in fireboxes requiring three siphons, and these arearranged as two side siphons and a center siphon. Heretofore, in threesiphon installations, it has been the practice to use a center siphon ofthe Nicholson type and two duplex type siphons, one spaced laterallyfrom each side of the center siphon. The reason why both types ofsiphons were heretofore employed in a three siphon installation, is thatwith duplex siphons as heretofore constructed, the two inlet necksthereof could not well be accommodated in the center of the rebox wherethe front throat sheet of the rebox has the least height.

One of the objects of the present invention is to provide a siphon ofthe so-called duplex type which is practical to install and use eitheras a single siphon arranged centrally in a relatively narrow firebox orto install or use in triplicate in a relatively wide rebox and arrangedas a center siphon and two side siphons respectively.

Another object of the invention is to provide a duplex type of siphon,which when used in multiple in a relatively wide rebox, has parts sodisposed therein as ably to support the brick of a fire arch without theaid of arch tubes heretofore necessary in a multiple siphoninstallation.

A further object of the present invention is to provide a siphon of thiskind which has greater exibility than has heretofore been possible, sothat it more ably accommodates itself to movement of the rebox sheetsdue to temperature changes, and this without damage to itself or to saidfirebox sheets.

Still a further object of the invention is to provide a siphon of thiskind that requires the making of a fewer holes in the sheets of theiirebox and may be installed at low cost.

Again, it is an object of the invention to provide a siphon of this kindin which it is possible to provide a greater volume of Water for thatpart of the siphon body subjected to the highest temperature wheninstalled inthe rebox of a locomotive boiler. l Y

Furthermore, it is an obect of the invention to provide a siphon of thiskind in which it is prac- Y tical to employ a smaller diameter tube asan inlet for a part of the body, which tube may be more easily bent tothe desired shape and which will have more flexibility to absorb thestresses imparted thereto, thus avoiding cracking or splitting.

The above mentioned objects of the invention, as Well as others,together with the several advantages thereof will more fully appear asthe speciiication proceeds.

In the drawings:

Fig. 1 is a longitudinalvvertical sectional view through the frebox endof a locomotive boiler and in which the improved thermic siphon has beeninstalled in triplicate.

Fig. 2 is a ,transverse vertical sectional View through the fireboxappearing in Fig. 1 as taken on the line 22 of said Fig. 1.

Fig. 3 is an end elevation of the improved thermic siphon as viewed fromthe front thereof 'taken on the line 8 8 of Fig. 1 and illustrates oneway whereby plain rectangular rebrick may be cut away at certain cornersto pass about the connection the auxiliary water inlet has with the maininlet of the improved siphon.

Fig. 9 is a View similar to Fig. 8 and illustrates a modified form ofbrick which may be employed to pass about the connection said auxiliarywater inlet has with the main inlet of the improved siphon.

Referring now in detail to that embodiment of the invention, illustratedin Figs. l, 2 and 3 of the accompanying drawings. 5 5 indicate the sidesheets of the rebox of a locomotive boiler and 6 indicates the crownsheet. 1 indicates the front or nue sheet thereof and 8 indicates the.back sheet thereof, the lower portion of the flue sheet being formed toprovide the inside throat sheet 9. It will be understood that the reboxis positioned in the rear end of the boiler shell which includes theouter side sheets III-IIJ, the usual top sheet Ia appearing in Fig. 2,back sheet II and outside front throat sheet I2. Portions of the backsheets 8 and II respectively, are formed to provide a fuel door I3.

The several sheets mentioned coact to form the side water legs I4, backwater leg I5 and front throat I6, all bottomed by a mud ring I1. Theabove is typical of a conventional locomotive boiler rebox and adjacentparts and requires no further description except to say that companionsheets are suitably staybolted.

The firebox, which as herein shown is a relatively wide one, is equippedwith a. plurality of improved thermic siphons I8 of the duplex type, inthis instance three in number. In Fig. 2, these siphons are shown asarranged one on the longitudinal median line of the flrebox andhereinafter referred to as the center siphon, and one spaced laterallyat each side thereof and hereinafter referred to as the side siphons.All three siphons are substantially alike. In general, each siphon I8 isa hollow water steaming and circulating element having ends that openthrough certain sheets of the flrebox at different elevations as willlater appear. When the nrebox is a relatively narrow one and only onesiphon is employed therein, then such a siphon is disposed in thelongitudinal median plane of the firebox and the boiler as a whole.

The improved siphon includes a nat hollow body I9 formed to providerelatively deep, front and rear end compartments or chambers 28 and 2Irespectively separated by an intermediate compartment 22 of less depth.The body includes laterally spaced side walls 23-23 and transverselyrounded front and rear end walls 24 and 25 respectively. The said sideand end walls are flared outwardly around the entire top end of the bodyto provide a laterally extending flange 26. This fiange is fitted andwelded in operative relation with respect to an associated longitudinalopening in the crown sheet 6. Thus the open top end of the body providesa common discharge for all three compartments 20, 2I and 22respectively, of the siphon body, into the steam and water space of theboiler above the crown sheet.

The front wall 24 of the body is disposed at a relatively steep angleextending downwardly and rearwardly from the crown sheet and providesbut a relatively small amount of overhang for this end of the body. Therear wall 25 of the body is disposed at relatively steep angle,substantially the opposite of that of the front wall, and extendsdownwardly and forwardly to merge into a rounded corner or nose 21.

Associated with said rear compartment of the siphon body is a downwardlyand forwardly extending tubular inlet neck 28 of substantial length. Thefront end of said neck is anchored in a flexible diaphragm 29 preferablyflanged up from the top portion of the inner front throat sheet 9 of thefirebox. The inlet neck 28 is of a diameter greater than the spacingbetween the side walls 23-23 of the body and the upper rear end of saidneck merges into the rear end of the body as a bulge 28a. that extendsaround the corner or nose 21 as best appears in Fig. 1.

The bottom portion of the front compartment 20 is formed as a stub-liketubular extension 30 disposed axially above and substantially parallelwith the neck 28. This extension has a diameter substantially coincidingwith the spacing between extremity of said other end is shown as being.

welded in an opening 32 formed in the top side of the inlet neck 28 toreceive the same.

In Fig. 4, the extremity of said curved end of the neck or tube is shownas being welded in a diaphragm 33, flanged upwardly from an integralpart of the neck 28. In Fig. 5 this diaphragm, which is indicated at 33ais made integral with an appropriately curved flange 33h which is weldedin a matching opening in the top side of the inlet neck 28. In Fig. 6,the extremity of said end is shown as extending partway into the inletneck 28 and there formed as a scoop or delector 3Ia, better to directwater into the auxiliary inlet tube or neck 3 I.

Fig. 7 illustrates a modified form of construction of that part of theinlet neck 28 that is attached in the throat sheet and which receivesthe inlet end of the auxiliary neck or tube 3 I. In Fig. '1, the inletend portion 28.1: of the inlet neck is of a diameter enlarged withrespect to the remainder of said neck and this enlarged inlet endportion is provided with a flange to receive the associated end of theinlet tube 3I. This arrangement permits of a better equalization of thevolume of Water, delivered to the front and rear end chambers of eachassociated siphon body.

Preferably the auxiliary inlet tube 3I, when made separate from theremainder of the siphon structure described, is formed from a pieceofseamless tubing. By making the inlet tube 3| as a part separate fromthe remainder of the siphon and by using tubing of lesser diameter thanthe neck, said inlet tube is easier to bend or form to the desiredshape.

The main inlet neck 28 has that downward and forward inclination desiredin a fire arch. When such an arch is desired in a firebox having threesiphons installed therein as best appears in Fig. 2, then said arch ismade up of two side rows of brick 34 and two intermediate rows of brick35. The lateral margins of both rows of intermediate brick are made fora good sealing engagement upon opposite sides of the inlet tube or neck28 of the center siphon and upon those sides of the neck or tube 28 ofthe side siphons which face toward the center siphon. The inner marginsof the brick 34 in the side rows are formed to engage upon the necks 28of the side siphons while the outer margins of said brick are made toengage against the side sheets 5 of the rebox for support.

It is to be noted from Fig. 2 that the spacing between the brick in theside and intermediate rows 34 and 35 thereof, is less than the width ofthe body, and, therefore, less than the diameter of the auxiliary inletneck 3| of the three siphons. Where the meeting faces of adjacent brickin said side and intermediate rows thereof are disposed in the plane ofthe auxiliary necks 3|, considered transversely of the firebox, cornerparts 35a of said bricks are cut away as appears in Fig. 8. When thebrick are arranged so that mid portions of brick in adjacent rows aredisposed in said plane as before mentioned, center parts of one end ofsaid brick are cut away as appears at 35h in Fig. 9.

It is apparent that while the body of each siphon has two inlet necks,they are so arranged that only one opening is required in the throatsheet 9 for each siphon. This effects a considerable saving ininstallation cost. While the inlet neck 28 is relatively large indiameter, it has such length as to impart to it the necessaryflexibility. Also, while the auxiliary inlet neck 3l is short ascompared With the inlet neck 28, it has a smaller diameter and includesa curved portion of relatively large radius that gives it theflexibility necessary to withstand service conditions.

It is apparent that the rear end chamber 2| of the body is disposed insuch position that it is exposed to the higher temperature in thefirebox and to the radiant heat of the re therein. However, as the inlettube 28 has a greater diameter than the inlet neck 32, it will deliver agreater volume of water into said rear end chamber than is 'deliveredinto the front end chamber which is subject to lesser temperature withthis arrangement. The rear compartment which is subjected to highertemperature cannot burn out because it receives an ample supply of waterto olset said higher temperature.

In the operation of the siphon installation appearing in Figs. l and 2,water is taken into each neck 28 of the three siphons from the frontthroat I6. A part of this water passes up each auxiliary neck 3| intothe front end chamber 20 of each siphon while the greater part passes upthe remainder of the neck 28, into the rear end chamber 2| of eachSiphon body. Water from both chambers enters the intermediate chamber 22of each siphon so that the hollow body of each Siphon is completelyfilled with Water. Due to the action produced by the siphons, water isdischarged from each one thereof through the crown sheet with a fountainaction. Therefore, it is assured that the crown sheet is always floodedeven under low water levels in the boiler.

In the manufacture of the siphon, that end of the neck 28 forwardlybeyond the auxiliary neck, will have such length as to adapt itsinstallation in a firebox of considerable length. For shorter reboxes,portions of said end of the neck may be cut off so that the siphons maybe readily made to t said shorter reboxes.

While in describing the invention, I have referred in detail to theform, arrangement and construction of the parts involved, the same is tobe considered only in the illustrative sense so that I do not wish to belimited thereto except as may be specilically set forth in the appendedclaims.

I claim as my invention:

l. In a locomotive boiler rebox, water steaming and circulating meanstherein, a body p0rtion and a downwardly and forwardly extending inletneck therefor in communication with the water space of the boiler, saidmeans including a second body portion spaced above said inlet neck atleast in part, an inlet neck for said second body portion, opening intothe rst mentioned inlet neck, a brick arch in the firebox comprisingaplurality of rows of brick having adjacent ends supported at least inpart on the rst mentioned inlet neck and being accommodated by thespacing of the second body portion above the first mentioned inlet neck,certain of the brick being formed to pass about that part of the secondmentioned inlet neck where it opens into the rst mentioned one.

2. A thermic siphon for use in a locomotive boiler rebox embodyingtherein a llat elongated hollow body comprising spaced apart sides andends formed to provide relatively deep front and rear compartments incommunication with each other, the two compartments having a commondischarge at the upper ends into the boiler, a downwardly and forwardlyextending tubular inlet neck of substantial length and of a diameter

